During the performance of physical exercise, the body is subjected to stresses and strains beyond that which would normally be encountered in most people's everyday activities. These stresses and strains increase the risk of injury occurring to vulnerable areas of the body such as the joints, and care should be taken to minimise such risks wherever possible during training.
In the performance of exercises for training the abdominal muscles, with which the present invention is concerned, the joint between the pelvis and the spine is particularly at risk. To minimise the risk of injury to this joint, it is thought to be beneficial to maintain the pelvis, so far as is possible during the performance of the exercise, in a position substantially at the mid-point of its range of anterior to posterior rotation about the joint. This position is referred to herein as neutral pelvic alignment.
Fitness equipment for training a user's abdominal muscles generally operates with the user in a supine body position. However, for users lacking mobility, such as those who are disabled, obese or elderly, it can be difficult comfortably to adopt the supine position, and even more difficult to return to a standing position afterwards. As a result, those users who are likely to benefit most from abdominal muscle training can find themselves excluded from performing such exercise.
In an attempt to overcome this problem, some abdominal exercise devices have been provided which offer the user the option of exercising from a seated position. However, such devices do not promote neutral pelvic alignment, leaving the user at an increased risk of injury.
The ideal body position for maintaining neutral pelvic alignment is referred to herein as the half-kneeling position. This involves the buttocks and knees only being supported, with a somewhat larger angle being formed between the abdomen and the upper legs than is customary in a normal seated position. Static seats, known as kneel chairs, which support a user in the half-kneeling position are well known and are widely used by those suffering from back trauma, as an aid to rehabilitation. However it is believed that, until now, no exercise apparatus has sought to support a user in the half-kneeling position for the performance of abdominal muscle training exercise. Furthermore, current designs of kneel chairs do not promote easy and safe mounting and dismounting of the seat, requiring the user to mount the seat from the front of the chair and to step back into the seat.
In addition to the above discussed concerns regarding neutral pelvic alignment, many known abdominal training devices suffer further shortcomings in that they rely solely on weight-stacks or elastic resistance elements to provide the resistive force which the user must overcome during exercise. The use of weight-stacks inevitably greatly increases the overall mass of the product, making it difficult and expensive to ship, and cumbersome to move once installed. A drawback involved in the use of elastic resistance elements alone is that the resistive load increases exponentially as the material is stretched. Unless used in combination with other resistive loads, this provides an unnatural load and decreases the specificity of the exercise, i.e. the targeting of a particular exercise to a particular group of muscles.